Database Systems, unit: Normalization. Core concepts, terminology, and worked-example cues a college student meets for this unit, building on prior units without repeating them. Front: a term, concept, or short problem cue. Back: the definition, explanation, or answer.
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- What is normalization?
- The process of organizing database tables to reduce redundancy and improve data integrity
- What is a normal form?
- A set of rules defining a level of database table organization and redundancy reduction
- What problem does normalization primarily solve?
- Data redundancy and update, insertion, and deletion anomalies
- What is an update anomaly?
- An inconsistency that arises when redundant data isn't updated in all its copies
- What is an insertion anomaly?
- An inability to add certain data without also having unrelated data present
- What is a deletion anomaly?
- The unintended loss of data when deleting a row that also holds other needed information
- What is First Normal Form (1NF)?
- A table where each column holds atomic values and there are no repeating groups
- What is Second Normal Form (2NF)?
- A table in 1NF where every non-key attribute depends on the whole primary key
- What is Third Normal Form (3NF)?
- A table in 2NF where no non-key attribute depends on another non-key attribute
- What is a partial dependency?
- When a non-key attribute depends on only part of a composite primary key
- What is a transitive dependency?
- When a non-key attribute depends on another non-key attribute rather than the key directly
- What is Boyce-Codd Normal Form (BCNF)?
- A stricter version of 3NF where every determinant must be a candidate key
- What is functional dependency?
- A relationship where one attribute's value determines another attribute's value
- What is denormalization?
- Intentionally introducing redundancy into a normalized design to improve read performance
- Why might a database be denormalized despite the risks?
- To improve query performance by reducing the need for joins
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